The present invention is generally directed to apparatus and methods for increasing the functional longevity and useful life of implantable medical devices while facilitating, shortening, and simplifying their implantation protocols. More particularly, the present invention is directed to apparatus and to associated methods for reducing mechanical stresses exerted on such medical devices by sutures and other surgical attachment mechanisms, both during and after implantation of the devices. Further, the present invention provides the implanting surgeon with easy to identify and use surgical attachment points which facilitate the implantation procedure relative to conventional devices and methods.
The surgical implantation of medical devices has long been known in the art. Presently, a number of surgical procedures utilize various implantable medical support devices and structures to stabilize organs and other anatomical structures at or near their original natural positions. As a result, these implanted medical devices and the associated surgical implantation procedures used to position them not only prevent or reduce anatomical deterioration of the supported organs and anatomical structures, but provide the added potential benefits of improving the function and, possibly, the functional life of the supported body part.
Such implantable medical support devices have been developed in a wide variety of structural and design configurations, depending upon intended need at the implantation site. For example, simple mesh slings or sheets of material have been used to reinforce abdominal walls following the protrusion of portions of the intestine. These mesh sheets have been formed of a variety of materials ranging from simple, biologically tolerable synthetic cloths to metals that are sutured into position. Alternatively, more exotic structures have been sutured between bones, for example, of the pelvis, to form supporting slings for abdominal organs and structures.
A specific example of one such commonly used medical implant is the urethral sling utilized for treating cases of recurrent urinary incontinence in females. Female recurrent urinary incontinence commonly develops from the loss or weakening of pelvic support of the urethra and/or bladder. Surgical corrective procedures have been developed for this condition which generally utilize a sling to add to the pelvic support of the abdominal organs, including the bladder or bladder neck in their natural positions.
Even though it is possible that the use of subsequent therapeutic protocols in combination with the patient""s natural healing process and the added support provided by the implanted sling may improve the naturally existing muscle support of the patient""s abdomen, medical implants such as these are intended to remain in stable condition in situ for extended periods of time, measured in years and even in decades. Therefore, it is important that slings and other implantable medical devices be designed with long term, stable functionality in mind.
One way to achieve this stability is to form the sling itself from biologically compatible materials in designs that will be compatible with normal physiological healing processes and that will retain their functional characteristics throughout years of use. Additionally, stable placement of the medical support devices during the implantation procedures also impacts this long-term functionality. For example, a urethral sling may be positioned across the appropriate portion of the abdominal floor to support the bladder or bladder neck by suturing opposing ends of the sling into position suspended from the pelvic structures, e.g., pelvic ischia, the lower most bones depending from each side of the pelvis. This positioning provides added stability beyond that available by simply suturing the sling to tissue structures and connective tissue.
Overall, medical implantation support techniques such as the above have enjoyed widespread success. However, there is always room for improvement. Under the present circumstances, it is known in the art that implanted medical devices such as these undergo physical changes over time as a result of the body""s natural healing and immune processes as well as the mechanical stresses imparted into and absorbed by the implants through repeated movement and use. Fabric weaves can shift and fibers can stretch, both contributing to decreases in the amount of support provided by the implant. Similarly, suturing holes in the implant materials may distort and stretch over time under the constant, concentrated forces focused into the sling materials by the direct contact of the fastening sutures cutting into the implants. This stretching and weakening may ultimately result in the inability of the implants to effectively perform their intended tasks, including that of support.
It is worth noting that fastening the implants into position with sutures remains as a very poplar technology. Though somewhat time-consuming during the implantation process, suturing provides the implanting surgeon with the degree of flexibility necessary to produce the best possible results with the implanted medical device. Still, the act of positioning the various sutures utilized in connection with conventional implantation techniques is rather time-consuming. In each case the surgeon must determine a suturing position within the implant material itself and then pass the suturing thread therethrough prior to attaching to pelvic structures, e.g., bony structure or stitching the sutures to softer tissue structures.
Accordingly, a need remains in the art for technologies and designs that can reduce the damage and stretching worn into implanted medical devices by sutures and surgical fastening devices, thereby increasing their functional longevity. A related need exists for technologies and designs that can simplify and facilitate the implantation of these devices.
These and other objects are achieved by the various apparatus and associated methods of the present invention.
In a broad aspect, the present invention provides novel apparatus that can be added or affixed to existing medical implants or incorporated into their original designs which will increase their functional longevity by distributing normal suture and medical fastener stresses throughout larger structural areas of the medical implants, reducing knifing and subsequent distortion. Utilization of these same devices also facilitates implantation of the medical implants by providing the implanting surgeon with readily identifiable guides, which both tactilely and visually direct the surgeon to the surgical fastener locations that are themselves easy to manipulate and employ during the surgical implantation procedure.
More specifically, the present invention provides readily adaptable apparatus for enhancing the functional longevity and for facilitating the implantation of medical devices through the provision of one or more reinforcing fastener guides fixed upon incorporated into the outer surfaces of the medical devices. Much like a curb or resistive barrier, the reinforcing fastener guides of the present invention provide a stable anchor to the medical implants themselves for the attaching sutures or other surgical attaching fasteners utilized to position the implants. In this manner, the reinforcing fastener guides provide a structural enhancement affixed to the medical implant that distributes compresses and tensile loads imparted into the implant by the surgical fasteners.
Moreover, at the same time, the reinforcing fastener guides of the present invention can be formed in a wide variety of shapes ranging from simple bars, arcs, and crescents to complete circles and polygons defining generally centrally located surgical fastener apertures within each. These novel reinforcing guides not only clearly define a readily discernible suture or fastening location within the implants, but also provide the implanting surgeon with both a visual and tactile indicator for quickly locating and employing the available fastening sites to fix the medical implants in position.
The reinforcing fastener guide apparatus of the present invention can be manufactured and formed from virtually any currently available or anticipated surgical implant materials. For example, biologically compatible materials suitable for the manufacture of implants include surgical grade stainless steel and titanium, ceramics, composites and fiber-reinforced materials, polymers, and bioresorbable materials. Accordingly, the apparatus of the present invention can be formed of any material that is suitable for use in connection with the desired implant. Further, this flexibility of manufacturing materials makes it possible to incorporate the reinforcing fastener guide apparatus of the present invention directly into the medical implants themselves during manufacture. Doing so eliminates another potential step in the implantation process by removing the need to attach or fix the reinforcing fastener guide apparatus to the implants prior to implantation itself.
Either way, if it is determined to be desirable to attach the apparatus of the present invention to an implant, one embodiment of the present invention includes fixation-interlocking mechanisms as part of the apparatus. An exemplary embodiment of the fixation interlocking mechanisms is a projecting pin with an enlarged head, which will penetrate or pierce the surface of the implant and lockingly engage thereto. Additional embodiments enhance this function by providing a complementary backing plate to the apparatus that will receive and lockingly engage the interlocking mechanisms.
An alternative embodiment of the present invention hinges the fastener reinforcing guide to the complementary backing plate so that it is possible to attach the apparatus of the present invention to an implant by positioning an edge of a planar surface of the implant between the hinged components of this embodiment of the present invention and simply snapping or latching the interlocking components shut. Doing so results in positioning the interlocking pins of the apparatus through the implant material into fixed engagement with the complementary backing plate, in a single motion.
In an additional embodiment of the present invention, the reinforcing fastener guide apparatus is also provided with at least one external ring. This ring can be fixed or rotatable about a pivoting attachment to the reinforcing fastener guide. It can function as a suture or surgical fastening aperture, which may be provided in the reinforcing fastener guide itself Alternatively, it can function to add additional fastener apertures to the one or more apertures previously provided in the body of the reinforcing fastener guide itself.
The present invention also provides associated implantation methods that utilize the novel features of the reinforcing fastener guides to simplify and facilitate the implantation of such medical devices. In a broad aspect these methods comprise the steps of fixedly mounting or attaching one or more reinforcing fastener guides of the present invention to one or more portions of the medical device to be implanted, prior to implantation of the device. It should be noted by those skilled in the art that this mounting step can be accomplished by the surgeon as part of the implantation procedure itself or, in the alternative, by the manufacturer of the medical implant, well in advance of the implantation procedure. The next step involves positioning the medical device within a patient""s body at the desired implantation site. Finally, at least one surgical fastener, such as a suture, is placed through each of the various reinforcing fastener guides present on the implant in order to secure the various attachment portions of the implant in place within the patient""s body.
In this manner, the implanting surgeon is able to rapidly position and secure the medical implant in-place utilizing the unique, clearly identifiable and easily locatable fastener apertures provided by each of the fixedly mounted reinforcing fastener guides of the present invention. Doing so not only shortens and facilitates the implantation procedure, but adds to the potential functional longevity of the implant itself by providing enhanced fixation locations that more evenly distribute tensile loads within the implant; thereby reducing wear and potential weakening of the implant over time.
For example, an exemplary urethral sling of the present invention can be provided with a plurality of reinforcing fastener guides fixedly mounted at opposing corners of the generally rectangular sling material support. Following a conventional surgical access procedure to the target implantation site, the surgeon simply positions the implant so that it can be secured into its proper location. However, unlike the prior art designs which require puncturing the sling material with a surgical fastener or, at a minimum, locating one of several provided suturing holes, the apparatus and methods of the present invention enable the surgeon to simply locate the reinforcing fastener guides and then placing an appropriate suture or other surgical fastening device such as a polymer or metal stud through the readily identifiable aperture in the reinforcing fastener guide to secure that portion of the implant in-place. This procedure is repeated for the each of the remaining reinforcing fastener guides until the implant is securely fastened in-place. The implantation procedure is then completed utilizing a conventional closure process.
A more detailed understanding of these features, and of additional features, objects, and advantages of the present invention will be provided to those skilled in the art from a consideration of the following Detailed Description of the Invention, taken in conjunction with the accompanying Drawings, which will now first be described briefly.